How do you replace a ABS rear wheel sensor? on 2001 Volvo V70 XC

How do you replace a ABS rear wheel sensor? The wheel end is obvious and clips leading up and forward. But it seems like the other end disappears under the gas tank. Do you have to take the gas tank out to replace that end? Help please,

You need to drop the fuel tank partially so you can replace the harness. However, I would be hesitant to replace the sensor, unless it is damaged or you have a measurable defect in the wiring/sensor. Do you have a fault in the ABS module for the rear sensor and that is why you are replacing it? If so, I bet you have a bad ABS Module, which is extremely common. I have replaced at least 50 of these for rear wheel speed sensor signals, especially the RR speed sensor. Look at this site, they rebuild the modules, http://bit.ly/8z7rcm